title: Alarm pheromone is detected by the vomeronasal organ in male rats.
abstract: It is widely known that a stressed animal releases specific pheromones, possibly for alarming nearby conspecifics. We previously investigated an alarm pheromone in male rats and found that this alarm pheromone evokes several responses, including increases in the defensive and risk assessment behaviors in a modified open-field test, and enhancement of the acoustic startle reflex. However, the role of the vomeronasal organ in these pheromone effects remains unclear. To clarify this point, vomeronasal organ-excising or sham surgeries were performed in male rats for use in 2 experimental models, after which they were exposed to alarm pheromone. We found that the vomeronasal organ-excising surgery blocked the effects of this alarm pheromone in both the modified open-field test and acoustic startle reflex test. In addition, the results of habituation/dishabituation test and soybean agglutinin binding to the accessory olfactory bulb suggested that the vomeronasal organ-excising surgery completely ablated the vomeronasal organ while preserving the functioning of the main olfactory system. From the above results, we showed that the vomeronasal organ plays an important role in alarm pheromone effects in the modified open-field test and acoustic startle reflex test.
authors.affiliation: Laboratory of Veterinary Ethology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan. akiyo@mail.ecc.u-tokyo.ac.jp.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Kiyokawa
authors.forename: Yuka
authors.initials: Y
authors.lastname: Kodama
authors.forename: Takahiro
authors.initials: T
authors.lastname: Kubota
authors.forename: Yukari
authors.initials: Y
authors.lastname: Takeuchi
authors.forename: Yuji
authors.initials: Y
authors.lastname: Mori
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D008297:Male; D009830:Olfactory Bulb / Q000502:physiology; D010675:Pheromones / Q000378:metabolism*; D037121:Plant Lectins / Q000378:metabolism; D051381:Rats / Q000502:physiology*; D017208:Rats, Wistar; D030262:Soybean Proteins / Q000378:metabolism; D013312:Stress, Physiological; D019147:Vomeronasal Organ / Q000502:physiology* / Q000601:surgery; D010835:Phytohemagglutinins
chemical_list: D010675:Pheromones; D037121:Plant Lectins; D030262:Soybean Proteins; C028824:soybean lectin; D010835:Phytohemagglutinins
keywords: acoustic startle reflex; habituation/dishabituation test; modified open-field test; soybean agglutinin